CHICAGO -- Twice before he had been prevented from pitching in the postseason -- due to an innings restriction in 2012 and an injury in '16 -- and yet here was Stephen Strasburg, nearly unable to pitch in a playoff game when his team needed him most. His name had become a punching bag for the past 24 hours as he caught criticism for the perception that he was not tough enough to pitch when he was sick.

The truth is Strasburg does not care about any of that criticism, even after his dominant, perception-changing outing in the Nationals' 5-0 victory in Game 4 of the National League Division Series, presented by T-Mobile, against the Cubs on Wednesday. He struck out 12 in seven scintillating innings and allowed just three Cubs hits. With each of the 106 pitches he threw as he battled flu-like symptoms, it was as if Strasburg was taking control of his own narrative.

In the city where Michael Jordan spent the prime of his professional career, call this Strasburg's version of the flu game. Call him Doctor October for curing the Nationals' postseason ills and willing his team back to Washington for a decisive Game 5 on Thursday night.

"It's a storybook," Nationals pitching coach Mike Maddux said. "He showed a lot of people what he's made of."

Through the windy, misty weather at Wrigley Field, Strasburg was brilliant. His changeup was bottomless as it generated a career-high 15 swings and misses. His curveball was sharp. His fastball location was pristine. The 12 strikeouts broke the franchise record for strikeouts in a playoff game that he himself set less than a week ago. Relievers Ryan Madson and Sean Doolittle both worked hitless innings to complete the shutout.

Strasburg became the first pitcher to throw seven or more scoreless innings with at least 12 strikeouts when facing elimination since Joe Coleman of the Tigers did so in Game 3 of the 1972 American League Championship Series.

"He throws that fastball and it rises and the changeup falls off the planet," Cubs first baseman Anthony Rizzo said. "Basically anyone who goes into the batting cage and doesn't know how to hit, that's what it feels like."

It ended a whirlwind 24 hours regarding who the Nationals would start in Game 4. Tuesday's postponement of Game 4 due to inclement weather meant that they could start Strasburg in this game on regular rest. However, the Nationals declared they were sticking with Tanner Roark because Strasburg was "under the weather."

Strasburg's dominant start

WSH@CHC Gm4: Strasburg K's 12 over seven scoreless

Stephen Strasburg strikes out 12 over seven scoreless innings to earn the win against the Cubs in Game 4 of the NLDS

That vagueness opened up Strasburg to heavy criticism, but it turns out he had a fever, chills and acute sinusitis. During his bullpen session on Monday, Strasburg felt weak and had no endurance. Even as late as Tuesday night, on the bus back to the team hotel he felt his chances of pitching were slim.

"Came in the other day and his face was the color of that carpet," Bryce Harper said, pointing to the green carpet in the visitors' batting cage.

The Nationals treated him the past few days with antibiotics, anti-inflammatories and fluid IVs and gave him a higher dosage through Tuesday evening. He woke up Wednesday morning feeling much better, so he called Maddux and went into manager Dusty Baker's office upon arrival and relayed the same message to both -- he wanted to start this game.

"I just gave it a night just to see how I'd feel; that if there was any chance, I was going to go out there," Strasburg said. "So I woke up and I was like, 'All right, let's do it.'"

Strasburg on his strong outing

WSH@CHC Gm4: Stasburg on his great performance

Nationals starter Stephen Strasburg talks about his outstanding outing for the Nationals in Game 4 of the NLDS

Neither general manager Mike Rizzo nor Baker believed Strasburg felt pressured into making this start. Rizzo also called the report inaccurate that Strasburg ever turned down the chance to start Game 4. None of his Nationals teammates said they tried to talk him into starting and a few even said they did not notice he was sick at all.

Strasburg added he did not feel as if he had something to prove.

"Not to [the media], no," he said. "You guys create the drama. But I know, I have faith in every other guy in this clubhouse and I know the coaching staff feels the same. So we're in it together, and when one guy goes down, you have to trust that the other guy is going to pick up the slack."

In two starts during this NLDS, Strasburg has yielded just two unearned runs and six hits in 14 innings with 22 strikeouts. He became the third pitcher to strike out at least 10 batters twice in any single Division Series, joining Justin Verlander (2012 and '13) and Cliff Lee ('10).

Strasburg's 22 K's in 22 seconds

Watch Strasburg's 22 strikeouts in NLDS in 22 seconds

Watch all of Stephen Strasburg's 22 strikeouts against the Cubs in the NLDS in 22 seconds

In the past, Strasburg has been robbed of these moments, unable to perform in the games that mattered most in October. Now, on the center stage in the postseason, Strasburg is excelling.

"When he's healthy and he's on the mound, he's one of, if not, the best pitchers in the game," Nats first baseman Ryan Zimmerman said. "Since the All-Star break, nobody has really been like him. To have him come out and do that in a spot like that, obviously ... huge is an understatement for us."

Jamal Collier covers the Nationals for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.